JP4646898B2 - Solvent that specifically dissolves ethyl cellulose - Google Patents

Description

  The present invention relates to a solvent that specifically dissolves ethyl cellulose and does not dissolve butyral resin. The present invention also relates to a vehicle obtained by dissolving ethyl cellulose in the solvent, and a paste obtained by mixing metal particles, organometallic compounds and / or glass particles in the vehicle.

  As a solvent used in the semiconductor field, a solvent that dissolves a resin, particularly ethyl cellulose, but does not dissolve a butyral resin is demanded. The reason for this is to prevent the sheet attack from being caused even if the printing process is performed on the surface of the green sheet during the production of the multilayer ceramic capacitor.

  In this field, a vehicle obtained by dissolving ethyl cellulose in a solvent and a paste obtained by mixing metal particles, organometallic compounds and / or glass particles in the vehicle are also useful. The reason is that printing can be accurately drawn by having an appropriate viscosity.

  However, in general, a solvent that dissolves ethyl cellulose is soluble in butyral resin, and a solvent that dissolves ethyl cellulose but does not dissolve butyral resin has not been known so far.

  Patent Document 1 discloses a conductive paste that is used by being applied onto a ceramic green sheet in the production of a multilayer ceramic capacitor and contains a binder resin, an organic solvent, and a metal powder. This conductive paste is characterized by using a specific polyvinyl acetal resin as a binder resin, and as an organic solvent, a general ketone (such as dipropyl ketone), ester (such as 2-ethylhexyl acetate) or It only discloses the use of carboxylic acids (such as butanoic acid).

  Patent Document 2 also discloses a conductive paste that is printed on a thin ceramic green sheet in the production of a multilayer ceramic capacitor, and includes a conductive powder, a binder resin, an organic solvent, and a dispersant. Is disclosed. This conductive paste is a dihydroterpinyl acetate as an organic solvent that stably dissolves the binder resin (ethylcellulose resin) in the conductive paste but does not dissolve the binder resin (for example, butyral resin) in the ceramic green sheet. It contains a single solvent or a mixed solvent of dihydroterpinel acetate and at least one of dihydroterpineol and a mineral oil having 10 to 20 carbon atoms.

JP 2005-259667 A JP 2005-197079 A

  Under such circumstances, the present inventors have sought to develop a solvent that sufficiently dissolves ethyl cellulose, has a certain degree of viscosity, and hardly dissolves butyral resin.

  As a result of various studies to solve the above problems, the present inventors have found that a solvent containing a specific ketal sufficiently dissolves ethyl cellulose, but hardly dissolves butyral resin, thereby completing the present invention. It came.

[式中、Ａはメチレンまたはエチレン基であり、Ｒ^１は、水素原子またはメチルもしくはエチル基であり、Ｒ^２およびＲ^３は、互いに独立して、炭素数１〜８のアルキル基であるか、または、Ｒ^２およびＲ^３は、それらが結合する炭素原子と一緒になって、炭素数６〜８のシクロアルカン環またはメチルもしくはエチル置換基を有する合計炭素数６〜８のシクロアルカン環を形成していてもよい]
で示されるケタールを含むことを特徴とするエチルセルロースに溶解性を示す溶剤を提供するものである。 That is, the present invention provides the following formula (I):

[Wherein, A is a methylene or ethylene group, R ¹ is a hydrogen atom or a methyl or ethyl group, and R ² and R ³ are each independently an alkyl group having 1 to 8 carbon atoms. Or R ² and R ³ together with the carbon atom to which they are attached, a cycloalkane ring having 6 to 8 carbon atoms or a cycloalkane ring having a total carbon number of 6 to 8 having a methyl or ethyl substituent. May be formed]
The solvent which shows the solubility to ethyl cellulose characterized by including the ketal shown by these is provided.

  The present invention also provides a vehicle in which cellulose is dissolved in the solvent, and a paste in which metal particles, organometallic compounds and / or glass particles are mixed with the vehicle.

The solvent of the present invention dissolves ethyl cellulose and does not dissolve butyral resin.
The vehicle of the present invention exhibits an appropriate viscosity and is excellent in printability.
The paste of the present invention does not cause sheet attack or deterioration of insulation when used for printing.

The ketal used in the present invention can be obtained, for example, by reacting a ketone and a diol in the presence of an acid catalyst.
Ketones that can be used include ketones having 3 to 10 carbon atoms. These are, for example, acetone, 2-butanone, 2-hexanone, 3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-octanone, 3-octanone, 4-octanone, 2-nonanone, 3-nonanone 4-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-decanone, 4-methyl-3-penten-2-one, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, ethylcyclohexanone, dimethyl Cyclohexanone, cycloheptanone, methylcycloheptanone, cyclooctanone, acetophenone, phorone, isophorone, camphor and the like.

Preferred ketones are 2-hexanone, 3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-octanone, 3-octanone, 4-octanone, 2-nonanone, 3-nonanone, 4-nonanone, 5- Nonanone, 2-decanone, 3-decanone, 4-decanone, 5-decanone, cyclohexanone, methylcyclohexanone, cycloheptanone, and cyclooctanone.
More preferred ketones are 2-octanone, 3-octanone, 4-octanone, cyclohexanone and methylcyclohexanone.
The most preferred ketones are 2-octanone, 3-octanone and 4-octanone.

Diols having 2 to 4 carbon atoms are included as diols that can be used. These are, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butylene glycol, 1,3-butylene glycol and the like. Preferred diols are ethylene glycol and propylene glycol.
Acid catalysts that can be used include acids that release protons, such as hydrochloric acid, sulfuric acid, nitric acid, and the like.

In the ketal production, the ketone and diol are used in a molar ratio of 1: 1 to 1: 2, preferably 1: 1 to 1: 1.5, more preferably 1: 1 to 1: 1.2. It's okay.
The reaction pressure may be normal pressure or reduced pressure.
The reaction temperature may be 60-120 ° C, preferably 70-110 ° C, more preferably 80-100 ° C.
The reaction is usually completed within a few hours, more usually within an hour, depending on the conditions.
A solvent may not be used, but a small amount of an organic solvent that does not participate in the reaction may be used if necessary. Organic solvents that can be used for this purpose are solvents azeotroped with water, for example benzene, ethyl acetate and the like.

  In general, the reaction between a ketone and a diol under an acid catalyst is a reversible reaction. In order to prevent an undesirable reverse reaction in this reaction, the produced water is removed by azeotropic distillation with benzene or the like. However, benzene has a negative impact on the environment and the human body. Therefore, it is desirable to carry out the reaction while removing produced water under reduced pressure.

  During the reaction under reduced pressure, water is distilled off first, then the unreacted starting materials ketone and diol are distilled off. These ketones and diols may be used for the next reaction. Finally, the reaction product, ketal, is recovered by distillation under reduced pressure. The ketal thus produced usually has a purity of 99% or more.

  The ketal produced as described above dissolves ethyl cellulose, but butyral resin aggregates and hardly dissolves. Therefore, these ketals can be used as a solvent that specifically dissolves ethyl cellulose. Examples of other resins that can be dissolved by these ketals include rosin, hydrogenated rosin, and acrylic resin.

  In addition to the specific ketals described above, the solvent of the present invention may contain other organic solvents up to 40%, preferably up to 20, more preferably up to 10%, most preferably up to 5% by weight of the ketal. Can be included. Organic solvents that can be used for this purpose are, for example, terpineol, dihydroterpineol, texanol, butyl carbitol acetate and the like.

  The vehicle of the present invention contains ethylcellulose in the solvent of the present invention in an amount of up to 20% by weight, preferably up to 15% by weight, more preferably up to 10% by weight (based on the weight of the solvent).

The paste of the present invention contains the vehicle of the present invention in an amount of 30 to 70% by weight, preferably 40 to 60% by weight, based on the weight of the paste, and the total amount of metal particles, organometallic compounds and / or glass particles. 70 to 30% by weight, preferably 60 to 40% by weight.
These metal particles, organometallic compounds and glass particles include nickel, titanium, magnesium, aluminum, zinc and silicon powders, and organic compounds containing these metals and powders of alloys of these metals.

The vehicle of the present invention can be produced by a conventional method, for example, by gradually adding and dissolving ethyl cellulose to the solvent of the present invention heated to 40 to 100 ° C. with stirring.
The paste of the present invention can be produced by kneading the vehicle of the present invention with metal particles, organometallic compounds and / or glass particles by a conventional method, for example, using a three roll mill. During the kneading, the solvent of the present invention can be added as a diluent as necessary.

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.
Purity analysis of the produced ketal was performed using gas chromatography. The measurement conditions are as follows:

Synthesis example 1
(1) A distillation tower equipped with a 1 L flask equipped with a thermometer and a cooling pipe was prepared as a distillation apparatus. The number of theoretical stages of this distillation column was 35, and the distillation apparatus was heated by a mantle heater.
The flask was charged with 256 g (2 mol) of 2-octanone and 168 g (2.2 mol) of propylene glycol and heated at 80 ° C. for 30 minutes under a pressure of 470 hPa. Thereafter, the pressure was reduced to 415 hPa to fractionate water.
(2) Next, the pressure was reduced to 110 hPa and the temperature was gradually increased to 100 ° C. On the way, unreacted 2-octanone was fractionated, and further, propylene glycol charged in an excessive amount was also recovered.
(3) When the pressure was further reduced and finally reduced to 20 hPa, the product 2-octanone propylene ketal was distilled. The amount of 2-octanone propylene ketal thus obtained was 309.2 g, and its purity was 99.92%.

Synthesis example 2
(1) Using the same distillation apparatus as in Synthesis Example 1, 384 g (3 mol) of 2-octanone and 204.6 g (3.3 mol) of ethylene glycol were charged into the flask, and the pressure was 450 hPa at 80 ° C. for 30 minutes. Heated. Thereafter, the pressure was reduced to 420 hPa to fractionate water.
(2) Next, the pressure was reduced to 100 hPa and the temperature was gradually increased to 100 ° C. In the middle of the reaction, unreacted 2-octanone was fractionated, and ethylene glycol charged in excess during the decompression to 80 hPa was distilled together.
(3) When the pressure was further reduced and finally reduced to 20 hPa, the product 2-octanone ethylene ketal was distilled. The amount of 2-octanone ethylene ketal thus obtained was 310.4 g, and its purity was 99.94%.

表中、×は、樹脂が膨潤して凝集した状態を表し、○は、樹脂が完全に溶解された状態を表す。表２より、本発明の溶剤は、ブチラール樹脂、エポキシ樹脂を溶解せず、エチルセルロース、水添ロジン、ロジン、アクリル樹脂を特異的に溶解することがわかる。 Example 1
Various resins were dissolved in the solvent of the present invention in an amount of 10% by weight. The test results are shown in Table 2 below.

In the table, x represents a state where the resin swelled and aggregated, and ◯ represents a state where the resin was completely dissolved. From Table 2, it can be seen that the solvent of the present invention specifically dissolves ethyl cellulose, hydrogenated rosin, rosin and acrylic resin without dissolving butyral resin and epoxy resin.

表３より、本発明の溶剤(２-ＯＥＫ、２-ＯＰＫ)は樹脂溶解前の粘度が低いにもかかわらず、それにエチルセルロースを溶解させたビヒクルは、ターピネオールやメンタノールにエチルセルロースを溶解させたビヒクルに匹敵する高粘度を示す。
また、本発明の溶剤の沸点は、ＢＣＡ、ＮＧ-１２０と比較して低いことから乾燥性は良好である。 Example 2
Ethyl cellulose was dissolved in an amount of 5% by weight in the solvent of the present invention and a solvent known as an ethyl cellulose solvent, and whether or not it was dissolved and the viscosity before and after the dissolution were measured. The viscosity was measured at 20 ° C. using an SV type viscometer. The measurement results are shown in Table 3 below.
In addition, Table 3 below shows the boiling point of each solvent under normal pressure as an index of the drying property of the solvent.

From Table 3, the solvent of the present invention (2-OEK, 2-OPK) has a low viscosity before dissolving the resin, but the vehicle in which ethyl cellulose is dissolved is a vehicle in which ethyl cellulose is dissolved in terpineol or mentanol. High viscosity comparable.
Moreover, since the boiling point of the solvent of this invention is low compared with BCA and NG-120, drying property is favorable.

表中、×は、樹脂が膨潤して凝集した状態を表し、△は、樹脂が溶解するが若干の白濁が確認された状態を表し、○は、樹脂が完全に溶解された状態を表す。
表４より、本発明の溶剤(２-ＯＥＫ、２-ＯＰＫ)は、積層セラミックコンデンサーや多層セラミック基板等に使用されるグリーンシートの成分であるブチラール樹脂に対する攻撃性が他の溶剤より低いことが判る。つまり、比較的薄いグリーンシート上に本発明のビヒクルを使用することができるので、より小さなセラミックコンデンサーや薄い複合基板を作成することができる。 Example 3
The results of examining the solubility of 5 wt% butyral resin in the solvents listed in Example 2 are shown in Table 4 below.

In the table, x represents a state in which the resin swelled and aggregated, Δ represents a state in which the resin was dissolved but some cloudiness was confirmed, and ◯ represents a state in which the resin was completely dissolved.
From Table 4, it can be seen that the solvent (2-OEK, 2-OPK) of the present invention is less aggressive to butyral resin, which is a component of the green sheet used in multilayer ceramic capacitors, multilayer ceramic substrates, and the like. I understand. That is, since the vehicle of the present invention can be used on a relatively thin green sheet, a smaller ceramic capacitor and a thin composite substrate can be produced.

Example 4
Solvent 2-OPK (450 g) of the present invention was heated to 70 ° C., and ethyl cellulose STD-100 manufactured by Dow Chemical Co., Ltd. was gradually added and dissolved therein while stirring. Next, the obtained vehicle (500 g) and a commercially available nickel powder (500 g) as a conductive metal powder were mixed and kneaded using a three-roll mill to completely disperse.
Using the paste of the present invention thus obtained, screen printing was performed by a predetermined method on the green sheet coated with butyral resin. Compared to a paste produced in the same manner using terpineol or mentanol as a solvent, the paste of the present invention significantly reduced the sheet attack on the green sheet.
As described above, it was shown that the sheet attack property is improved by using the paste of the present invention, and it is useful for thinning the multilayer ceramic capacitor.

Claims (2)

The following formula (I):

Wherein, A is a methylene or ethylene group, R ¹ is hydrogen atom or a methylation group, R ² is a methyl group, R ³ is hexyl]
Vehicle comprised of in ketal represented by dissolving the ethylcellulose in including SOLVENTS. A paste comprising the vehicle according to claim 1 mixed with metal particles, an organometallic compound and / or glass particles.